This invention relates to a heater device that is disposed in the gas flow path of a short duration wind tunnel to modify the temperature profile of the gas exiting the heater element.
Recent gas turbine research has centered around using a shock tunnel or a pressurized supply tank as a short duration source of heated, pressurized gas to duplicate the corrected flow conditions (flow function and corrected speed) encountered in the gas turbine environment. All of the measurement programs conducted to date by the present assignee of this application have used actual engine hardware. The temperature profile at the inlet of a high pressure turbine vane row has been very uniform by design. It is well known that a non-uniform temperature profile at the high pressure turbine vane inlet would better represent the exit profile of an upstream combustor. However, until this time, the experimental sophistication had not advanced to the point where such a non-uniform profile could be properly utilized.
There is therefore a need for a heater that could be placed in the entry duct leading to the turbine stage such that a non-uniform temperature distribution could be produced. The desired exit temperature profile would be parabolic in the radial direction with the centerline temperature approximately 100.degree. R higher than the temperature of the incoming flow.